there is a tool for this, but you can use a tape measure. Must be in mm. When you go into SDD and select Suspension Calibration, you will need to enter ride height for each wheel. The measurements are taken from the center of the wheel to the fender lip. Enter the numbers as measured on the vehicle. Common Air Suspension Problems. When air suspension fails, you'll know it. The most likely first symptoms are a lower, sagging ride height, or the selectable ride settings that no longer function. Other symptoms include a rougher, noisier ride, and sloppy handling through corners and over bumps. Fortunately, a failed air suspension component is b17bed said: I can not get my air suspension switch to work anymore,it worked when i got it i have checked the two fuses they are ok.It has had a new suspension done 18 months ago the Range Rover suspension stayes up but i can not do anything with it, can any one help please.cheers bill uk. Just had the the bill to repair air suspension switch. SOURCE: Air suspension inactive, HDC inactive, ABS light on, Range Rover. Air Suspension Inactive usually means there is a problem with the Air Suspension. However, it will also come up when alternator or battery voltage is low, or when you reset (disconnect and then connect) the battery. How to clear air suspension inactive over and over again and get a diagnoses using this tool save time and money going to a garagehttp://www.rswsolutions.com Turning the steering full lock left and right (which has worked before when only the "air suspension inactive" fault was showing) 2. Hard reset on the battery (disconnect and touch opposing leads together) 3. Plugged two different diagnostic tools in (one Delphi professional system and one nondescript handheld, neither of which have specific Turn the vehicle on and raise air suspension all the way to off road height. Let it run for 60 seconds. Raise the car to standard height - then to off road height - then back down to standard height. This will both reset the system, purge it of any bad air and its an effective way of blowing off the system. 1. The automatic suspension system on a Land Rover must be placed in a service mode (High Lock) prior to raising the vehicle on a frame-contact hoist. This can only be accomplished by using a Land Rover Test Book Scan tool or an aftermarket equivalent. 2. KEOFI.